1. Field of the Invention
The present invention relates to a lathe, more particularly to a lathe with an auxiliary transverse table capable of machining a workpiece in a high straightness degree.
2. Description of the Prior Art
A lathe is a machine which can be used for machining a workpiece into a shape or for cutting the same as desired.
Generally, when a workpiece is machined into a predetermined shape by using a lathe, the workpiece is placed between a drive spindle and a tail stock of the lathe and then the workpiece is rotated by the drive spindle about its longitudinal axis. A turning tool or the like is fastened to the transverse table mounted on a cross table which turnig tool can be driven perpendiculary to the workpiece axis by the movement of the transverse table and can be driven parallel to the workpiece axis by the movement of the longitudinal table, so that a rotational machining of the workpiece can be accomplished in the conventional way.
U.S. Pat. No. 5,090,278 (issued to Hans Mair, et al.) discloses a lathe which can machine a workpiece with one transverse table at one side.
When machining a workpiece using the above conventional lathe, since the workpiece is machined by a tool at one side, the workpiece is subject to a loss of its straightness by its weight and by friction heat between the workpiece and the tool despite a coolant supplied therebetween.
Particularly, many difficulties in maintaining a straightness of the workpiece exist in a workpiece such as a long lead screw used for a disk player since it has a diameter much smaller than its length.
Therefore, there exists a problem in that it is difficult to machine a long workpiece in a high straightness degree at one time.